Persistent Pulmonary Hypertension of the Newborn due to Alveolar Capillary Dysplasia

Abstract

Three unrelated female term infants died when less than 1 month old from intractable pulmonary hypertension associated with deficient capillaries in airspace walls, anomalous small pulmonary veins in bronchiolar-arterial rays, and medial thickening in small pulmonary arteries together with peripheral muscularization. This complex uascular abnormality in the lungs has been termed alveolar capillary dysplasia and/or misalignment of lung uessels in seven previously reported cases. Each infant also showed abnormally immature parenchymal development in the lungs, as was noted in four of the seven prior cases. One had phocomelia; four of the seven prior cases had a variety of congenital anomalies. The primary pulmonary uascular anomaly is likely to be a failure of fetal lung uascularization dating from the second trimester and to be due to action of an unknown teratogen. Centroacinar veins may represent bronchial veins that do not normally develop beyond the ends of cartilaginous bronchi. Pulmonary arterial occlusive changes are interpreted, as reactive to obstruction at the level of pulmonary arterioles.

Key Words:

• fetal lung development
• fetal lung vascularization
• alveolar capillary dysplasia
• misaligned lung uessels
• persistent pulmonary hypertension of newborn
• pulmonary hypoplasia